I want to know if there is an API to create a datagrid like here:
http://socghop.appspot.com/gsoc/program/accepted_orgs/google/gsoc2010
From these:
http://roberto.open-lab.com/2010/01/18/javascript-grid-editor-i-want-to-be-excel/
I choose http://www.datatables.net/. It is extreme flexible, up to date and has a good documentation, well tested.
jqGrid is not free. And Flexigrid is two years old and comes with jQuery 1.2.x.
There are several:
As well as many others...
My personal favorite is jqGrid, which is extremely flexible and can do pretty much everything you need. On the other hand the API can be a bit overwhelming when you are first getting started. You also might be interested in jqGrid-PHP which is integrated with your server-side PHP code - but it is not free.